The role of surface barrier oxidation on AlGaN/GaN HEMTs reliability

Reliability of AlGaN/GaN HEMTs processed with different surface oxidation levels was studied using electrical and optical methods. It was found that HEMTs with more surface oxide content are more susceptible to degradation in terms of gate leakage and trapping characteristics, although this oxide layer initially passivates surface traps. In the degraded devices, trap level with activation energy of 0.45–0.47 eV was observed and attributed to surface related traps. This indicates that oxygen may play a crucial role for AlGaN/GaN HEMT reliability.

► We studied reliability of AlGaN/GaN HEMTs with different surface treatment.
► Different surface treatment resulted in different surface oxide content.
► AlGaN/GaN HEMTs with higher surface oxide content are more susceptible to degradation.
► Our results indicate that oxygen may play a role for AlGaN/GaN HEMTs reliability.